# Draft California 2012 Integrated Report( 303(d) List/305(b) Report)

# Supporting Information

## Regional Board 6 - Lahontan Region

Water Body Name: | Silver Creek (Lassen County)
Water Body ID: | CAR6411001220080811105509
Water Body Type: | River & Stream

DECISION ID | 26555 | Region 6
Silver Creek (Lassen County)

Pollutant: | Dissolved oxygen saturation
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. One of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 or Table 3.2 of the Policy. 3. One of two samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26555, Dissolved oxygen saturation | Region 6
Silver Creek (Lassen County)
LOE ID: | 25925
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. Dissolved oxygen saturation levels in two samples were 81 and 66 percent.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The regionwide narrative objective in the Lahontan Basin Plan states: "The dissolved oxygen concentration, as percent saturation, shall not be depressed by more than 10 percent, nor shall the minimum dissolved oxygen concentration be less than 80 percent of saturation."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26606 | Region 6
Silver Creek (Lassen County)

Pollutant: | Fecal Coliform
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Both of the two samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 or Table 3.2 of the Policy. 3. Two of two samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26606, Fecal Coliform | Region 6
Silver Creek (Lassen County)
LOE ID: | 25932
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. The fecal coliform counts in two samples were 350 and 57 colonies per 100 mL. (Because the objective requires a minimum of five samples in a 30-day period, a log mean was not calculated.)
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 26606, Fecal Coliform | Region 6
Silver Creek (Lassen County)
LOE ID: | 25933
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. The fecal coliform counts in two samples were 350 and 57 colonies per 100 mL.(Because the objective requires a minimum of five samples in a 30-day period, a log mean was not calculated.)
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26610 | Region 6
Silver Creek (Lassen County)

Pollutant: | Nitrate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. Neither of two samples exceeds the California Maximum Contaminant Level. The single annual average datapoint (calculated from two samples) does not exceed the site-specific water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Neither of two samples or the single annual average datapoint exceeded the applicable water quality objectives and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded.

Line of Evidence (LOE) for Decision ID 26610, Nitrate | Region 6
Silver Creek (Lassen County)
LOE ID: | 25928
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. Two samples had NO3-N concentrations of 0.06 and 0.07 mg/L. The MCL was not exceeded.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate is 45 mg/L expressed "as nitrate," equivalent to 10 mg/L expressed "as N."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 26610, Nitrate | Region 6
Silver Creek (Lassen County)
LOE ID: | 25927
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. Two samples had NO3-N concentrations of 0.06 and 0.07 mg/L. The "annual average" based on these two samples was 0.065 mg.L.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The site specific objective for "Bear Creek" in Lahontan Basin Plan Table 3-7 applies through the Tributary Rule. It is an annual average of total nitrogen concentration of 0.1 mg/L
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26605 | Region 6
Silver Creek (Lassen County)

Pollutant: | Oxygen, Dissolved
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Both of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 or Table 3.2 of the Policy. 3. Two of two samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26605, Oxygen, Dissolved | Region 6
Silver Creek (Lassen County)
LOE ID: | 25924
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 2
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. Two samples had dissolved oxygen concentrations of 6.91 and 6.29 mg/L..
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The applicable water quality objective, from Lahontan Basin Plan Table 3-6, is a 1-day minimum dissolved oxygen concentration of 8 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26611 | Region 6
Silver Creek (Lassen County)

Pollutant: | Phosphate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological data are available to assess whether the two phosphate samples comply with the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. No biological data are available for assessment of compliance with the objective.. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26611, Phosphate | Region 6
Silver Creek (Lassen County)
LOE ID: | 25929
Pollutant: | Phosphate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. Two samples had PO4-P concentrations of 0.31 and 0.37 mg/L.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan does not include site-specific objectives for phosphate in this water body. The regionwide narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26607 | Region 6
Silver Creek (Lassen County)

Pollutant: | Sediment
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: One line of evidence is available in the administrative record to assess this pollutant. The water quality objective for sediment is antidegradation based. The single available sample cannot be used to document baseline and trend conditions to assess compliance with the objective using Listing Policy section 3.10. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy (both samples were collected within one month. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. The single sample is insufficient to assess compliance with the objective under section 3.10 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26607, Sediment | Region 6
Silver Creek (Lassen County)
LOE ID: | 25934
Pollutant: | Sediment
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled sediment at one Silver Creek station in August 2002. The suspended sediment concentration in one sample was 233.9 mg/L.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's narrative objective states: "The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station, Station 6, was sampled.
Temporal Representation: | One sample was collected on August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26280 | Region 6
Silver Creek (Lassen County)

Pollutant: | Specific Conductance
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Neither of two samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 or Table 3.2 of the Policy. 3. Neither of two samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26280, Specific Conductance | Region 6
Silver Creek (Lassen County)
LOE ID: | 25922
Pollutant: | Specific Conductance
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. Specific conductance levels in 2 samples were 157 and 204 uS/cm. The MCL was not exceeded.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Consituents" objective. The MCL for specific conductance is 900 microsiemens per centimeter (uS/cm).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26330 | Region 6
Silver Creek (Lassen County)

Pollutant: | Temperature, water
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: One line of evidence is available in the administrative record to assess this pollutant. The water quality objective for temperature is antidegradation-based. The two available samples cannot be used to document baseline and trend conditions to assess compliance with the objective using Listing Policy section 3.10. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy (both samples were collected within one month). 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. The two available samples are insufficient to assess compliance with the objective under section 3.10 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26330, Temperature, water | Region 6
Silver Creek (Lassen County)
LOE ID: | 25926
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. Two samples had water temperatures of 23.32 and 17.96 degrees Celsius.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The relevant sections of the Lahontan Basin Plan's temperature objective are as follows: "The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction fo the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses. For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26329 | Region 6
Silver Creek (Lassen County)

Pollutant: | Turbidity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of of evidence are available in the administrative record to assess this pollutant. Neither of the two samples exceeds the California Maximum Contaminant Level. The narrative water quality objective for turbidity is antidegradation-based and the two samples are insufficient to assess baseline and trend conditions under section 3.10 of the Listing Policy. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 or Table 3.2 of the Policy. 3. Neither of two samples exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. The two samples are insufficient for assessment of compliance under Listing Policy section 3.10. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains the same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26329, Turbidity | Region 6
Silver Creek (Lassen County)
LOE ID: | 25931
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. The turbidity levels in two samples were 24.2 and 15.4 NTU.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for turbidity is 5 NTU.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 26329, Turbidity | Region 6
Silver Creek (Lassen County)
LOE ID: | 25930
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. The turbidity levels in two samples were 24.2 and 15.4 NTU.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide turbidity objective states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):

DECISION ID | 26339 | Region 6
Silver Creek (Lassen County)

Pollutant: | pH
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | Regional Board Conclusion: This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: One line of evidence is available in the administrative record to assess this pollutant. The water quality objective for pH is antidegradation-based. The two available samples cannot be used to document baseline and trend conditions to assess compliance with the objective using Listing Policy section 3.10. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy (both samples were collected within one month). 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. The two available samples are insufficient to assess compliance with the objective under section 3.10 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 26339, pH | Region 6
Silver Creek (Lassen County)
LOE ID: | 25923
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Bureau of Land Management sampled two Silver Creek stations in August 2002. Two samples had pH levels of 8.14 and 8.39 units.
Data Reference: | Water quality data for surface waters on U.S Bureau of Land Management lands in Lassen and Modoc Counties
SWAMP Data: | Non-SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's objective for pH states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Two stations, Stations 4 and 6, were sampled.
Temporal Representation: | Samples were collected on August 6 and August 23, 2002.
Environmental Conditions: | Silver Creek is a tributary of Bare Creek, in Lassen County. Bare Creek is a tributary of Lower Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, it is designated for the Spawning, Reproduction and Development use. The site- specific water quality objectives for "Bear Creek" in Basin Plan Table 3-7 apply to Bare Creek and its tributaries.
QAPP Information: | No quality assurance information was submitted with the data.
QAPP Information Reference(s):